The present invention relates to apparatus for displaying alphanumeric information and more particularly to an improved character generator for a keyboard display terminal or the like. More specifically, the invention relates to a display wherein the characters displayed are in the form of dot patterns selected from a character memory which receives address information from a keyboard or computer identifying the character to be displayed. Part or all of the dot pattern of the character to be displayed is provided at the output of the character memory.
Often, the character memory is embodied in the form of a read only memory integrated circuit module which can be replaced by different read only memory modules to display the different character sets of different languages. More recently, plural languages have been provided in a single character memory and characters common to one or more languages are shared by the languages to avoid the need for duplicating common characters. One such character generating system is disclosed in U.S. Pat. No. 4,122,533. The system of this patent provides a multiplexor 26 and a plurality of language symbol selecting programmable read only memories 44 between the refresh buffer 40 and the character generator read only memory 42. The use of translating or directory memories between the refresh buffer and the character generator presents a significant cost and level of complexity. It is also known that a limited address field can be used with a register of extra bits to access a memory larger than could be defined by the address field alone. The prior art teachings as exemplified by U.S. Pat. No. 4,057,848 are complex and expensive however and not suited for use in a display.